This disclosure relates to multilayer films, methods of manufacture thereof and to articles comprising the same. In particular, this disclosure relates to multilayer films that comprise polyolefins and starch.
Films for food, industrial and specialty packaging are under pressure to reduce their impact on the environment due to their origin based on oil derivatives such as ethylene. There is a growing interest in using films for packaging that contains components that are renewable or that are based on materials that are not derived from fossil fuels (hereinafter “environmentally friendly materials”). Usually these environmentally friendly materials undergo deterioration in film performance over time which makes them unsuitable for packaging applications. In addition, their mechanical performance is poor when compared with other films and this necessitates an increase in film thickness that offsets any improvement in sustainability. In order to overcome these drawbacks, polymers such as polyethylenes are often added to the environmentally friendly materials.
Films containing polyolefins and starch (an environmentally friendly material because it is produced from renewable resources and is compostable) are useful in a variety of different applications. Common applications for such films are packaging, containers, separators, dividers, or the like. One of the drawbacks of these films that if the processing temperature or temperature of usage rises above the thermal stability temperature of starch the films begins to smoke. Another drawback is the optical clarity of such films which tend to be hazy and not optically clear.
It is therefore desirable to develop films that comprise polyolefins and starch where the ability to smoke is minimized and that are optically clear.